Services may be performed by a system based upon requests received from client devices, such as authentication requests, requests for content (e.g., emails, messages, news content, videos, music, bank account information, etc.), requests to perform actions (e.g., setting up user accounts, sending emails, sending messages, uploading content to platforms, transferring funds, etc.), etc. Levels of activity of the client devices may be monitored, and client devices having levels of activity greater than an activity threshold may be blocked (e.g., temporarily, permanently, etc.) in order to prevent malicious users and/or internet bots from abusing the system.